Process of making reenforced flooring or the like



Patented Nov. 2, 1926.

UNITED STATES JAMES H. STEDMAN, OF BBAINTREE, MASSACHUSETTS.

PROCESS OF MAKING REEHFORCED FLOORING OR THE LIKE.

No Drawing.

- This invention relates to the manufacture of sheet rubber compounds reenforced by cotton fibre, or its equivalent, and more particularly to a process of making a variegated sheet of this nature which may be vulcanized and used for various purposes but which is especially useful as a floor or wall covermg.

'In my Letters Patent of the United States No. 1,482,952, granted February 5, 1924, I have disclosed the underlying essentials and have defined the characteristic features of the product obtained by a practice of the process hereinafter described, and I have also explained one process that may be practiced in its manufacture. I have discovered that many economies and improvements may be effected in the manufacture of the reenforced sheet rubber compound by varying the nature of the process specifically described in said patent to the extent and within the limitations hereinafter set forth.

The object of the invention is to provide an improved and economic process for manufacturing a variegated, reenforced' rubber flooring, or the like, having the characteristic features described in my prior patent hereinabove named.

To the accomplishment of this object the invention consists in the method of making a variegated, reenforced rubber com ound in sheet form, the preferred manner 0 practicing which is hereinafter described and defined in the appended claims. 4

In practicing the present process I prefer to obtain the fibrous material, which reenforces the finished product, from. rubber waste which contains cotton fibre or its equivalent, hereinafter termed friction, since this material furnishes a cotton fibre conveniently and cheaply. It should disenforcing fibre may initially be in the form of spun, raw or cleaned cotton, or cotton waste, or in fact, in any convenient or ex .pedient form. Those skilled in the art will recognze that in the manufacture of a var egated sheet the important consideration is the incorporation of a fibrous reenforcing medium that will function to retard or re-.

sist an interfiow of the colors, during the period of mixing required to reduce such of the colors to masses of relatively small bulk as may be requisite to form the desired mottled appearance of the finished article. If the composition of such a sheet is not reen- Application filed March 21, 1924. Serial No. 700,950.

forced then the mixing steps, if continued to the point where the colors are reduced to small masses, will cause the colors to blur and cause the surface to present a smutty appearance. The colors will not be distinct 1y defined.

I first cut up the friction into relatively small pieces, a beam cutter being conveniently used for this purpose. The friction, in this form, is fed little by little to a differential mill, called a refiner, whch flattens the pieces and bruises the contained fibre. This material, in larger quantities, is successively fed to other refiners, havng their rolls set closer and closer together, which sheets the friction and progressively breaks down or shreds the fibre. the refiners is a sheet of friction reduced to substantially parchment thickness and condition which serves as a container for the fibre which is thoroughly distributed through it and is now so finely shredded or The final product from comminuted as tobe almost imperceptible to the eye. Any combination of rubber and fibre which is to be substituted for the friction will be treated in like manner so as to .obtain a similar parchment-like, fibre-bearing rubber sheet.

The required amount of the refined friction in the form just described, which is of a neutral or grey-rubber color, is weighed out for use as the reenforcing ingredient of each color compound in accordance with the particular formula used in preparing these compounds. The composition of each compound as to the rubber, pigment and the like, may be the same. except for the variation of the color pigment.

' The color compounds or batches are mechanically mixed by being separately fed to a Banbury or other patent mixer, and tinctly be understood, however, that the rethen to a warmed mixing mill which sheets the product from the mixer and produces a color stock in the form of a plastic mass. In the color stock thus produced the shredded fibre is thoroughly distributed throughout the whole mass of the batch.

facturing any pattern for which orders are in hand.

From this point the process-of manufac- I ture proceeds as described in my prior patent, hereinabove referred to, that is, the Warm color stocks are first blended together on a mixing mill and the rough sheet thus obtained is finished on a calender. The selection of color stocks is determined by the particular pattern to beproduced, and it should be understood that in this art white and black are classed as colors. Different patterns -require the colors in differing proportions. Usually a greater quantity of one color stock is used to form the base or back ground of the pattern, one or more other colors being mixed therewith, as may be required to surface.

The final blending of the color stocks takes place on the calender and the variegated mass 'of rubber is there reduced to apredetermined thickness. When a threeroll calender is used a backing sheet may be applied as the sheet is fed out between the central and lower rolls. The operation at the calender is the same as usual the mass of rubber being banked at the feed side and drawn through the rolls between side guides that determine the width of the sheet.- The oalendered sheet may be wound on a mandrel and thereafter cut into the lengths desired for vulcanizin according to whether a floor runner is.to be produced or smaller mats or tiles.

An extremely important step in the process is the preparation and distribution of the fibrousireenforcing medium which, as described, preferably is cotton fibre as found in friction. However the original admixture of uncured rubber and fibre is ob tained. it will be observed that before the reenforcing fibre isintroduced to a color compound it is properly prepared to perform its function of causlng the colors to resist interflow when a plurality of the color compounds are blended on the mixing mill and calender. Furthermore the comminutproduce the desired mottled ed fibre is carried by or held inthe parch-' ment-like sheet that is produced from the last refining mill to which the friction, or

like combination of rubber and fibre, is introduced. By thismethod it is unnecessary to handle the reenforcing medium as a separate element. It is shredded, or otherwise prepared, while held in the uncured rubber. The result of this is that when added to the compound the fibre can not bunch, but necessarily becomes evenly distributed through the colored stock and, wherever introduced. acts to the same ole gree in each instance as a color interflow retardative medium to irisure a retention of the individual identities of the colors in the completed variegated sheet. This results in a uniformity of design and beauty in the final product that adds materially to its attractive appearance.

Having thus described the novel process and the nature of the article produced when practicing its underlying principle, what is claimed as new, is

v 1. The method of making a variegated, reenforced rubber flooring, or the like, which comprises reducing friction to small pieces, refining the friction, first little by little to merely flatten the pieces and bruise the contained fibre and then in larger quantities in a manner to comminute the fibre and finally sheet the material until a parchment-like sheet is obtained having the comminuted fibre thoroughly distributed therethrough, adding this material as an ingredient in making a color compound, forming a color stock therefrom, mixing a plurality of color,

stocks in a manner to produce a variegated sheettherefrom, and then vulcanizing the sheet.

2. The method of making a variegated, reenforced rubber flooring, or the like which comprises passing a combination of uncured rubber and cotton, or like fibre, successively through a plurality of refining mills which ultimately refine the batch to a parchment-like sheet with the fibre held in the sheet in a finely comminuted condition and evenly distributed therethrough, utilizing the fibre in this form as an ingredient of a color compound, forming a color stock therefrom, mixing a plurality of color stocks in a manner to produce a variegated sheet therefrom, and then vulcanizing the sheet.

3. The method of making a variegated, reenforced rubber flooring, or the like, which comprises producing a fibre-bearing sheet by passing a combination of uncured rubber and cotton, or like fibre, successively through a series of refining mills that act to progressively reduce the fibre in magnitude and simultaneously-reduce the thickness of the sheet that is formed, until the fibre is held throughout the sheet in the form of fine shreds, making a reenforced color stock by includingthis fibre-bearing sheet as an ingredient of the compound, and mixing a plurality of color stocks in a manner to produce a variegated sheet therefrom.

4. The method of m'aking a variegated, reenforced rubber flooring, or the like, which comprises treating accumulations of uncured rubber having a contained cotton ing sheet to a color compound as the res ns forcing ingredient thereof, forming a color stook therefrom, and then producing a variegated, reenforced sheet by mixing a plurality of color stocks together.

5. The method of making a reenforced color stock for rubber flooring which com- Prises producing a fibre-bearing sheet by passing a combination of uncured rubber and cotton, or like fibre, successively through a series of refinin mills that act to progressively reduce the fine in magnitude and simultaneously reduce the thickness of the sheetthat is formed, until the fibre is held throughout the sheet in the form of fine shreds, then adding this fibre-bearing sheet to the rubber and pigment of the color compound, and finally mixing all theingr'edients of thehcom ound until the 'color pig ment and shi'e ded ,fibre are thoroughly distributed throughout the batch.

6. The-method of making a variegated, reenforced rubber. flooring, or. the like, which comprises making a plurality of color compounds, differing as to color, but each of which includes a reenforcing ingredient comprised ofa rubber sheet of parchmentlike thickness saturated with a finely comminuted cotton, or like fibre, reducing each compound to a plastic state with the fibre thoroughly distributed therethrough, then mixing the plastic color stocks thus formed in a manner to produce a variegated sheet, and finally curing the sheet. 1 7. The method of making a'reenforced color stock for rubber flooring which comprises compounding rubber, pigment and shredded cotton, or like fibre, while contained in a sheet of uncured rubber of parchment-like thickness, mechanically'mixing' the ingredients, and then reducing the mixture to a plastic mass in which the color pigment and shredded fibre are thoroughly distributed throughout the batch.

' JAMES H. STEDMAN. 

